4 ALASKAN GLACIER STUDIES Thumb are the southernmost Alaskan glaciers seen from the steamer, Patterson Glacier being visible from the north end of Wrangell Narrows. The increase in glaciation with increase in latitude may be shown by the lower snowline on Mt. Sumdum, than on the mountains to the south, as well as by the presence of tidal glaciers. Larger glaciers appear now, the shorter arm of Baird Glacier being sixteen miles long, the longer tributary being certainly over 17 miles; but its whole length has not been mapped. They advance from vast snowfields whose extent is not yet known. Some, notably the Dawes and Baird, are through glaciers, or ice tongues which flow in opposite directions from a common, flattish, snow-covered divide. Some of the glaciers of this region bifurcate so close to their terminus that one name is used for both arms, as in Baird Glacier. The name Dawes is used for two adjacent glaciers which formerly were one. The same is true of the Sawyer Glaciers. The extreme glacial erosion and the lack of glacial deposits in southern Frederick Sound has been pointed out by the Wrights.1 Klotz determined that LeConte Glacier retreated a half mile between the time of making a Coast Survey chart, probably in the late eighties, and 1893.* The bay it enters is called Hutli or Thunder Bay from the noise made by the discharge of icebergs, according to John Muir who visited this glacier in 1879.8 Icebergs then filled the bay for ten or twelve miles. Patterson Glacier was advancing and destroying trees in 1891 according to the Pacific Coast Pilot of that year.4 Baird Glacier, not to be confused with the other Baird Glaciers of the Tasnuna River and White Pass, has been studied by Klotz,6 who determined its rate of movement and rate of melting in 1894. Holkham Bay, at the base of Mt. Sumdum, with its branches Endicott and Tracy Arms, is said by Muir8 to be one of the most interesting Alaskan fiords. It has four tidal glaciers and a hundred or more glaciers of the second and third class. The icebergs interfere with navigation by large boats and it is often difficult to reach the tidal glaciers in small canoes. The unnamed ice tongues of Speel and Whiting Rivers are exceedingly attenuated, narrow glaciers, 6 or 7 miles long and a tenth to a quarter of a mile wide. Glaciers of TaTcu Inlet, This beautiful fiord just south of Juneau, is visited annually by thousands of tourists and the Taku Glacier has become one of the best known in Alaska, especially during the past 15 years when Muir Glacier has been less accessible and has lost beauty through retreat and loss of height. Within the fiord are also the Norris, Wright, and Twin Glaciers, besides a few smaller glaciers up the Taku River,7 but the Taku Glacier is the only one discharging icebergs. These glaciers are shown on iseveral maps 8 and there are also innumerable smaller glaciers. Muir says forty-five glaciers are visible from a steamer sailing up the middle of Taku Inlet.9 i Wright, F. E. and C. W., Bull. 347, U. S. Geol. Survey, 1008, p. 24 and PI. m. «Eotz, Otto, Geog. Journ., Vol. 14, 1899, p. 582. * Muir, John, Amer. Geol., Vol. XI, 1893, p. 291. * Reid, H. F., Variations of Glaciers, Journ. Geol., Vol. VHI, 1900, p. 168. • Klotz, Otto, Journ. Geol., Vol. HI, 1895,, pp. 512-518. i Muir, John, Harriman Alaska Expedition, Vol. I, 1901, p. 125. ' Hayes, C. W., Nat. Geog. Mag., Vol. IV, 1892, p. 151. i TJ. S. Coast and Geod. Survey, Charts 8050, 8300; Atlas of Award, Alaskan Boundary Tribunal, Sheets 12 and 13; PL 19, Vol. IV, Nat. Geog. Mag., 1892; PI. XXXVI, Bull. 287, Ui S. GeoL Survey, 1906. - • Muir, John, Harriman Alaskan Expedition, Vol. 1,1901, p. 125.